A combustion engine, especially of the piston type, may use a fuel injector for injecting fuel into a combustion chamber. The fuel injector comprises a filter assembly that is commonly press-fitted into the injector in an axial direction during manufacturing the injector.
EP 1 229 239 A2 shows a fuel injector with such a filter. The filter assembly comprises a filter element and a tubular filter housing for receiving the filter element. The filter element has a side wall with a shoulder for supporting an axial end of the filter element on the filter housing.
As the filter assembly is press-fitted into the injector, considerable axial forces may act against the side wall in a region of the shoulder. The filter element may deform temporarily or permanently so that the position of an upper section of the filter assembly with respect to the injector may be poorly defined. In addition, considerable tension may occur between the shoulder and the axial end of the filter element. This may lead to a rupture of the filter element so that unfiltered fuel may pass towards the delicate valve system of the injector.